PSI - Issue 70

Anchal kaw et al. / Procedia Structural Integrity 70 (2025) 161–168

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such as Time history method provided better results but they involve complex mathematical calculations. The main aim of this study was to provide recommendations to current seismic codes to upgrade and improve the codal provisions for NSEs as they are inadequate (Pinkawa et al., 2014) 3. Methodology The methodology for this study involves comparative study of design lateral forces acting on NSEs in a Hospital and Commercial building as per Indian code IS16700:2023(Criteria for structural safety of tall buildings) with IS 1893:2016 (Part 1)(Standard, 2016) provides various provisions for the seismic design of non-structural elements. It explains how various equipment and different type of electrical, mechanical and plumbing system in a building are subjected to earthquake shaking at locations where they are supported and connected to structural elements. It provides guidelines for both type of cantilever projections such as vertical projection (example: - tower, chimney, tanks etc.) and horizontal projection (example: -brackets, cornice etc.). The recommendations for seismic design of NSEs provided in IS 1893:2016 are completely inadequate and unclear. IS 16700:2023 provides guidelines for the seismic design of both acceleration- sensitive as well as displacement- sensitive NSEs laid down by various statutory and non- statutory bodies and the respective owner of the particular building. Different type of displacement- sensitive NSEs are attached to the building at various levels and the non-structural elements are connected to structural elements by supports and they should allow relative displacement at its ends when they are subjected to lateral loading due to seismic base excitation. The lateral forces acting on different type of acceleration sensitive NSEs due to seismic base excitation is defined in code and is calculated as per the formula. This formula however doesn’t consider the effect of time period of both structural components as well as non -structural components. Time period of NSEs as well as SEs have a major effect on the performance of the building. If the time period of NSEs resonates with the time period of the building a phenomenon known as resonance takes place which ultimately leading to the collapse of the building. Thus, our Indian standard codes need upgradation as the provisions provided by them underestimate the seismic demand which causes failure of NSEs and affects the behavior of building making it dysfunctional. The NDMA (National Disaster Management Authority) also provides data about safety of hospital buildings during critical events like earthquake. These guidelines are important for critical and lifeline structures like hospitals to function properly post-earthquake and are not applicable to other buildings such as commercial buildings, residential buildings etc. The NDMA guidelines ( Index Previous Next , 2016.) are essential to protect the collapse of critical structures. The expected performance of a hospital and commercial building during earthquake shaking has been compared below in Table 1. Eurocode 8 Part 1 (Design of structures for earthquake Resistance). 3.1. Review of existing Seismic codes and Guidelines for NSEs

Table 1. Expected performance of a building during earthquake shaking ( Reducing the Risks of Nonstructural Earthquake Damage-A Practical Guide FEMA E-74 , 2012)

Intensity of earthquake

Commercial building

Hospital building

Expected performance level of Commercial building

Expected performance level of Hospital building

Mild

No damage

No damage

Structural elements (SEs)

Moderate Minor damage No damage

Life safety (LS)

Immediate occupancy (IO)

Severe

No collapse

Minor damage

Non-Structural elements (NSEs)

Mild

No damage

No damage

Moderate Slight damage Functional

Immediate occupancy (IO)

Fully operational (FO)

Severe

-

No permanent damage